Colchicine (Colcin) is a natural product that is an inhibitor of microtubule polymerization (IC50=3 nM) and blocks microtubule polymerization by binding to microtubule proteins. Colchicine can be used in the treatment of ventilation and rheumatic diseases.

Thiocolchicoside (Thiocolchicine 2-glucoside analog) (Muscoril, Myoril, Neoflax) is a muscle relaxant with anti-inflammatory and analgesic effects. It acts as a competitive GABAA receptor antagonist and also glycine receptor antagonist with similar potency and nicotinic acetylcholine receptors to a much lesser extent. It has powerful convulsant activity and should not be used in seizure-prone individuals.